In order to facilitate the process of replenishing automated teller machines (ATMs) it is common for cassettes to be used to store bank notes, both in the ATM and in transit to and from ATMs. An empty ATM cassette can simply be removed from the ATM and replaced with a cassette which has been pre-filled with bank notes.
ATM cassettes are an attractive target for thieves, since they may contain 2000 bank notes or more, and are particularly vulnerable to theft during transportation and delivery to an ATM. To deter thieves, it is commonplace for ATM cassettes to be provided with spoiling or degradation systems which dispense an indelible dye, ink, or other spoiling or degrading agent onto the notes in the event of an attempted theft, thereby rendering the notes unusable.
In some spoiling systems a dispensing mechanism for dispensing the spoiling or degrading agent is mounted in a lid of the ATM cassette. However, due to complex design and variations between models of ATM cassette it is not always possible to mount the dispensing mechanism in the lid.
One solution to this problem is to mount the dispensing mechanism in the base of the ATM cassette. However, this can reduce the note carrying capacity of the ATM cassette, thereby increasing the frequency with which the cassette has to be replaced or replenished. This is undesirable, as ATM operators typically have to pay a fee to a licensed security company for replenishing the ATM, and thus reducing the frequency of replenishment of the ATM reduces cost for the ATM operator.
A common method of implementing a base-mounted dispensing mechanism is to store the spoiling or degradation agent in a cylinder or bore, with a piston being used to compress the spoiling or degrading agent on actuation of a spoiling or degradation system, forcing the spoiling or degrading agent through a valve and subsequently onto the notes contained in the ATM cassette. A problem with this type of system is that in order to obtain a satisfactory seal between the piston and the bore to ensure that there can be no leakage of the spoiling or degradation agent, the bore must be machined from a metal such as aluminium. The weight of a metallic bore produced in this way which is large enough to hold sufficient spoiling or degrading agent to spoil 2000 notes is substantial. Given that a cash in transit company will typically handle a large number of ATM cassettes at one time any excess weight is highly undesirable. Moreover, the cost of manufacturing a bore with sufficient precision to ensure a good quality seal between the bore and the piston and to prevent skewing of the piston in travel is prohibitive.